I know it "doesn't matter much" if I'm doing my own PROMs later on, but other than the fact that the 2nd is CA calibration, does anyone know the difference between

87 5.0-F M/Trans(M39) Calif, 3.45(GM3) 16071137 1139ACYD

and

87 5.0-F M/Trans(M39) Fed, 3.45(GM3) 16071119 1122ACXZ


( info from https://www.thirdgen.org/newdesign/faq/thirdgen.shtml )

I am running 3.73's so I figured going w/ the PROM for a 3.45 stick geared car would be better. Currently I have an 86 automatic IROC PROM & my mods are in the sig.

Since I'm at altitude, would the CA calibration be a bit leaner (which might work better for the thinner air here) ?

Any downfalls to going w/ the 87 PROM in an 86 setup? I'm pretty sure the only real diff was the alternator hookup & the dual fans...

thanks

 

Screw it. The federal PROM will be in next week.